Pneumatic buffer for self-propelled vehicles.



MELVILLE P. HAYWARD, OF QUINCY, MASSACHUSETTS.

PNEUMATIC BUFFER FOR SELF-PROPELLED VEHICLES.

Specification of Letters Patent.

Patented March 9, 1909.

AApplication filed May 9, 1907, Serial No. 372,671. Renewed August 21,1908. SerialNo. 449,744.

To all whom 'it may conce/m:

Be it known that l, MELVILLE P. HAY- WARD, a citizen of the UnitedStates, residing at Quincy, in the county of Norfolk and State ofMassachusetts, have'invented new and useful Improvements in PneumaticBuffers for Self-Propelled Vehicles, of 'which the following is aspecification.

This invention relates to shock absorbers or bufiing devices intendedfor use in connection with self-propelled vehicles so as to permit easyrunning and movement of the veln'cle body and prevent the transmissionof shocks from the running gears thereto.

The invention has for one of its objects to improve and simplify theconstruction and operation of devices of this character so as to becomparatively easy and inexpensive to manufacture and keep in repair,thoroughly reliable and ecient in use, and of substantial and durabledesign.

A further object of the invention is the provision of a plurality ofhollow iston-containing cylinders in which are co ed bodies of elasticand hydraulic media that cooperate to absorb the shocks exerted on thedevice, means being employed for equalizing the air or elasticmedium inthe chambers.l

rA further object is the provision of a pneumatic buffer comprising aplurality of aircontaining cylinders in which are arranged pistons ofspecial form, and an additional cylinder in which is Va vhydraulicmedium through which a piston ehurns back and forth under movement ofthebody of the vev hicle to which the buffer is applied.

. With these objects in view and others, as will appear as theydescription proceeds, the invention comprisesthe various novel featuresof construction and arrangement of parts Which will be more fullydescribed heremafter and set forth with particularity in the claimsappended hereto.

In the accompanying drawing, which illustrates one of the embodiments ofthe invention, Figure 1 is a central vertical section of the devicepartly in elevation. Figs. 2 and 3 are bottom plan views of modifiedforms of piston for the middle cylinder. Fig. 4 is a detail sectionalview of a modified form of main cylinder.

`Referring to the drawing, 1, designates a suitable base-plate on whichare fixed spaced upright main cylinders 2 and a central or intermediatesecondary cylinder 3. In each of the main cylinders 2 is a hollowpiston' 4 closed at its up er end bya cup 5 provided with apertured ugs6, and secured to the lugs of the pistons is a cross-head or bar 7hingedly connected at its ends to the pistons by the bolts 8. By thismeans a limited unequal movement of the pistons is permitted. On theupper ends of the cylinders are glands or packing nuts 8 that hold undercompression suitable packing rings 9 resting on the u per ends of thecylinders, thus preventing lea age of liquid from the latter. yTofurther assist in preventing leakage, the lower ends of the pistons areeach interiorly reduced to provide a relatively thin and yieldableannulus 10 Which is forced outwardly radially into in-,

timate contoact with the internal wall of the cylinder by the pressureof the li uid so that the greater the pressure in the cy inders, thetighter will the thin portions 10 of the pistons enga e the cylinders.Arranged in each cylin er is an upright pipe 11 open at its upper end,and the lower ends of the pipes are connected by a passage 12 in thebase plate so as to constitute an equalizing means for permitting thepressure in one cylinder to be the saine as that in the other, thusinsuring the uniform vertical movement of the pistons.

In each of the cylinders 2 is a body of oil or othersuitable liquid thatis somewhat below the upper end of the pipes 11 for the purpose ofaffording a large air space t9 give the pneumatic cushioning effect. Theair pressure is .established in the cylinders by means of an air pumpthat is adapted to be connectedwith a valve 5 on one ofthe cylinder caps5, the valve being of that type commonly employed in pneumatic tires.

ln the secondary cylinder 3 is a piston 13 having a plurality ofvertically extending ports 14 through which the oil or other hydraulicmedium iilling the cylinder 3 can pass back and forth to opposite sidesof the piston, as the latter reciprocates. The piston is provided with arod 15 that is bolted to the cross-head 7 so that all of the istons willmove simultaneously. The mid le cylinder and piston constitute aresistance device for preventing sudden and excessive movement of themovable elements 4 and in order to permit the parts to move up and downuite freely within certain limits above and be ow the central position,the cylinder 8 is provided with vertically extending channels 3 in itsinternal Wall that are of different lengths so as to permit fluid toreadily pass the piston 13 during the first part of its movement ineither direction and gradually resist the' by-passing of the liquid asthe` piston moves farther and farther from the central position. lnother words, the central piston and cylinder produces a graduallyincreasing resistance against the movement of the elements 4 of the maincylinders. The channels 3 may be cast or otherwise formed in thecylinder and the latter bored so that the piston will make a good fittherein. If desired, the cylinder does not require to be bored but maybe fitted with a lining 3a, as shown in Fig. 4, which is provided withapertures 3b communicating with the channels 3c of the cylinder.

In order to prevent a positive check or shock by the piston 13 movingpast the longest channel 3 under extreme shocks or blows sustained bythe vehicle, the piston 13 has a plurality of ports 14 through which theliquid can pass from one side`of the piston to the other. These portsare controlled by a fiap valve 16 for retarding the passage of theliquid upwardly and uppet valves 17 for resisting the downwardpmovementof liquid. The valves 17 are provided with stems 18 that are engaged bysprings 19 that tend to hold the valves seated. The springs 19and Hapvalve 16 are secured to a stem 20 extending through the piston rod 15.The flap valve 16 springs away from the ports when the pressure of theliquid on the upper side of the piston reaches a certain point, as doalso the valves 17 when the pressure on the underside becomes greatenough. 'The valve 16, 'as shown in Fig. 2, may be provided with ports16 which can be brought into complete or partial register with the ports14, thereby controlling the freedom with which the liquid can pass tothe bottom side of the piston.

In ractice, the buffers are attached toa vehic e in such a manner thatthe pistons will move up and down to follow the relative movementbetween the wheels and body of the vehicle. The compressed air in theupper ends of the cylinders 2 will be coinpressed upon the downwardmovement of the head 7 and thus cushion the shocks that would betransmitted to the vehicle body and the expansion of the air assists toreturn the parts in normal position. Any excessive and violent movementof the vehicle body is retarded or checked by the cylinder and piston 3,this checking occurring, however, more or less gradually, so as toeliminate the transmission` ofshocks to the vehicle body.

From the foregoing description, taken in connection with theaccompanying drawing, the advantages of the construction and of themethod of o eration will be readily apparent to those s ed in the art towhich the invention appertains, and while I have described the principleof operation of the invention, together with the apparatus which I nowconsider to be the best embodiment thereof, I desire to have itunderstood that the ap aratus shown is merely illustrative and t at suchchanges may be made when desired, as are within the scope of the claims.

Having thus described the invention, what I claim is y 1. In a device ofthe class described, the combination of a plurality of main pistoncylinders, the cylinders each containing a body of liquid and comressible fluid, equalizing means between t e cylinders, means for'onnecting the pistons, and a h draulic check; device connected with thesai means. 2. In a device of the class described, the combination of aplurality of cylinders adapted to contain a body of liquid and acompressible iluid, pressure equalizing means between the portionsk ofthe cylinders containing the compressible fluid, aA hollow piston ineach cylinder provided with thin walls that yieldingly engage theinternal surfaces of the cylinders under the pressure of the liquidtherein, and packings on the cylinders and disposed around the istons.

3. In a device of the c ass described, the combination of a plurality ofcylinders adapted each to containa'body of liquid and a compressibleiiuid, a"common,base plate having a passage, and open-ended tubeconnected with the passage and extending into the air ,space of thecylinders, pistons in the cylinders, means for connectin the pistons toact in unison,and a hydrau 'c check device for retarding' the movementof the pistons.

4. In a device ofthe class described, the combination of a plurality ofparallel cylinders each adapted to hold a body of li uid and elasticfluid, hollow pistons in the cy 'nders, caps for the outer ends of thepistons,

a cross head hingedly connected with the ca s, a secondar cylinderadapted to be iillled with a liquid, a piston movable back and forththerein and provided with ports, valves controlling the ports, and aconnectionbetween the cross head and the piston in the secondarycylinder.

5. In an apparatus of the class described, the combination of aplurality of parallel cylinders, relatively movable elements therein,there being a body of liquid and compressible fluid in each cylinder, adevice for connecting the elements to move in unison, means forconnecting the iiuid spaces of the cylinders permanent y together, ahydraulic checking device associated with the cylinders and includin amovable element, and means for positive y connecting the movableeleme'nt with the device.

6. In an apparatus of the class, described, the combination of a baseplate, a pair of parallel cylinders secured to the base plate andcontaining a bod of liquid and of com-- pressible Huid, cham ered istonsmovable 1n the cylinders, upright tu 'es mounted on the base plate 'andextending vu Wardly through the cylinder and' into the c ambers of thepistons, a conduit connecting the ends ofthe tubes to ether, a crossmemberhingedly connected Wit `the pistons, a hydraulic motionv checdevice supported on `the base plate and disposed between the cylinders'said device having al movable element; and

means for connecting the element lWith-the said member. p f 7. In anapparatus ofthe class described the combination with cushioning means,of a retarding device associated therewith, said devicecomprising acylinder having longitudinal channels mits internal wall, a lining forthe cylinder having apertures communieating with the'channels, a istonmovable in the cylinder, ports in the piston, and valves 'controllingthe orts.

In testimon Whereo I aix my-.signature yin presence'o j two witnesses.MELVILLEP. Witnesses: 1

CLIFFORD B. DANIELS,A BERTHA R. DANIELs.

